Fill the grid with the digits 1 to 6. Each row, column and 3x3-box has exactly one of each digit and 3 empty cells. The clues along the edges tell you which digit you can see from that vantage point. If you rotate the grid 180 degrees, the empty cells will appear at the same location as they appeared without the rotation.

Fill in the grid so that every row, every column, and every 3x3 box contains the digits 1 through 9. The even clues along the edges tell you which digit is the first even digit from that vantage point. The odd clues along the edges tell you which digit is the first odd digit from that vantage point.